SEOUL -- South Korean President Moon Jae-in has shaken up his cabinet by appointing close associates to senior positions, part of an effort to build up his political muscle ahead of the general election scheduled for April 2020.

Moon's chief of staff, Im Jong-seok, has been replaced by Noh Young-min, the ambassador to China, the presidential Blue House said Tuesday. Moon also picked Kang Gi-jung, a one-time lawmaker, to be the senior secretary for political affairs, a liaison role between the Blue House and parliament.

Prompting the staff changes is the 2020 general election. Multiple officials in the Blue House, including Im, are expected to run under the ruling Democratic Party of Korea banner. Politicians will start preparing for election season this spring.

The Democratic Party is basically split into three factions: Moon's group which supported the late former President Roh Moo-hyun; a clique that keeps its distance from Moon; and a neutral contingent with strong ties to citizen organizations.

When Moon assumed office in May 2017, he made appointments that struck a balance between all those factions. Instead of installing a close ally as chief of staff -- and risking accusations of cronyism -- Moon picked Im, part of the citizens' group faction.

This time around, Moon has called on two close allies to serve in his cabinet. Noh served as co-chair of Moon's failed presidential campaign in 2012, and also worked for Moon during the 2017 run. Kang also was a part of the latest campaign.

South Korean presidents serve one five-year term, and Moon is due to leave office in 2022. Therefore, he faces a lame-duck period during the latter half of his presidency. The battle to emerge victorious in the general election will be a powerful narrative in Moon's government this year and next. But because it is the party that steers parliamentary elections, the influence of the Blue House tends to be weaker in comparison.

Noh is a leading figure in the Democratic Party, having served three terms as a legislator in the National Assembly. Moon seeks to boost his influence within the party by bringing Noh closer. The president appointed Kang for similar reasons.

The cabinet reshuffle comes at a sensitive time in South Korean-Japanese relations. South Korean courts have ordered Japanese companies to pay former wartime laborers reparations, rulings that Tokyo has denounced. Separately, Japanese defense officials have accused the South Korean navy of training a fire-control radar on a Japanese patrol plane, a charge Seoul has rejected.

However, Noh's resume does not contain much obvious experience in handling Japan-related matters. It remains to be seen if his background as a Chinese envoy will translate into successful diplomacy with Japan.

Moon's latest moves could worsen ties with some factions in his party, as well as opposition parties. A Dec. 21 poll by Gallup Korea shows the president's disapproval rating climbing to 46%, above approval of 45%. It got there in large part due to economic woes. If Moon leans too strongly toward filling his inner circle with allies, that could weaken his position further.